One common type of lead-acid battery utilizes so-called "spiral-wound" cell elements. Such spiral-wound cell elements include thin plates and separators which are layered and then rolled into a spiral.
The housings for batteries having spiral-wound elements typically incorporate a container which has a plurality of cup-shaped cell cavities. The internal volume of the cell cavity is adapted to receive the cell elements. The cell cavities are usually interconnected by intercell partitions, defined at mutual tangent zones, and a cover is provided. The cover encloses the container and provides sufficient head space to install appropriate element straps, intercell connections, terminals, pressure-release valves, and the like.
Due to the various dimensional and performance requirements imposed on battery manufacturers by vehicle manufacturers, it would be desirable to manufacture batteries having different electrochemical capacities but the same external dimensions. Since the cell elements determine in large part the capacity of a battery, the chemical composition and the design of the plates may be varied to provide different capacities. This approach, however, is not always desirable, especially for relatively small variations among a line of batteries designed for similar applications. Changing plate design and variation of plate composition entails a corresponding increase in the number of plate manufacturing processes.
It is, however, relatively easy to vary the capacity of an element by varying the size of the plates. For example, a plate may be reduced in length or height, thereby reducing the electrochemical surface area and capacity of the cell element.
Reducing the height or length of the plates, however, necessarily reduces the height or width of the resulting spiral-wound element, and the cell cavities for a spiral-wound battery typically are uniformly sized to receive cell elements having a specific maximum electrochemical capacity. Thus, it would be necessary to reconfigure the other battery components to accommodate smaller capacity cell elements. This involves, at a minimum, redesign of the container, and may involve, at even greater expense and inconvenience, redesign of the cover and top lead.
It is an object of the subject invention, therefore, to provide various multicell, lead-acid batteries with spiral-wound elements, whereby the batteries have different electrochemical capacities but substantially the same external dimensions.
Another object is to provide such batteries which may be manufactured and assembled more easily. A related and more specific object is to provide such batteries which utilize a common container and cover.
Yet another object is to provide such spiral-wound, multicell, lead-acid batteries wherein all of the above advantages are realized.
Those and other objects and advantages of the invention will be apparent to those skilled in the art upon reading the following description and upon reference to the drawings.